first mobile gql sample

.eslintrc

@@ -1,10 +1,6 @@
 {
     "root": true,
-    "extends": [
-        "eslint:recommended",
-        "plugin:@typescript-eslint/recommended",
-        "plugin:@typescript-eslint/stylistic"
-    ],
+    "extends": ["eslint:recommended"],
     "env": {
         "jest": true,
         "node": true

lib/rules/no-more-than-2-fields.ts

@@ -0,0 +1,79 @@
+import { Kind, NameNode } from 'graphql';
+import { GraphQLESLintRule, GraphQLESLintRuleContext } from '@graphql-eslint/eslint-plugin/';
+
+const RULE_ID: string = 'no-more-than-2-fields';
+
+export const rule: GraphQLESLintRule = {
+    meta: {
+        type: 'suggestion',
+        hasSuggestions: true,
+        docs: {
+            description: 'Object should have no more than 2 fields.',
+            category: 'Operations',
+            recommended: true,
+            examples: [
+                {
+                    title: 'Incorrect',
+                    code: /* GraphQL */ `
+          query getSA($recoridId) {
+            uiapi {
+              query {
+                ServiceAppointment() {
+                  edges {
+                    node {
+                      Id
+                      Subject {
+                        value
+                      }
+                      AccountId {
+                        value
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+          `
+                }
+            ]
+        },
+        messages: {
+            [RULE_ID]: 'Field number should not exceed 2!'
+        },
+        schema: []
+    },
+    create(context: GraphQLESLintRuleContext) {
+        function checkNode(usedFields: Set<string>, node: NameNode): void {
+            const fieldName = node.value;
+
+            usedFields.add(fieldName);
+            if (usedFields.size === 3) {
+                context.report({
+                    node,
+                    messageId: RULE_ID
+                });
+            }
+        }
+
+        return {
+            SelectionSet(node) {
+                if (node.type === 'SelectionSet') {
+                    const rawNode = node.rawNode();
+                    // Traverse backwards to find 'node' from GraphQL ASTNode
+                    const parentNode = node.parent.rawNode();
+
+                    if (parentNode.kind === 'Field' && parentNode.name.value === 'node') {
+                        const set = new Set<string>();
+
+                        for (const selection of rawNode.selections) {
+                            if (selection.kind === Kind.FIELD) {
+                                checkNode(set, selection.alias || selection.name);
+                            }
+                        }
+                    }
+                }
+            }
+        };
+    }
+};

test/lib/rules/no-more-than-2-fields.ts

@@ -0,0 +1,65 @@
+import { RuleTester } from '@typescript-eslint/rule-tester';
+import { rule } from '../../../lib/rules/no-more-than-2-fields';
+
+const ruleTester = new RuleTester({
+    parser: '@graphql-eslint/eslint-plugin',
+    parserOptions: {
+        graphQLConfig: {}
+    }
+});
+
+ruleTester.run('@salesforce/lwc-mobile/no-more-than-2-fields', rule as any, {
+    valid: [
+        {
+            code: /* GraphQL */ `
+                query getSA {
+                    uiapi {
+                        query {
+                            ServiceAppointment {
+                                edges {
+                                    node {
+                                        Id
+                                        Subject {
+                                            value
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            `
+        }
+    ],
+    invalid: [
+        {
+            code: /* GraphQL */ `
+                query getSA($recId: string) {
+                    uiapi {
+                        query {
+                            ServiceAppointment(
+                                where: {
+                                    and: [{ AccountId: { eq: "1" } }, { Status: { eq: "New" } }]
+                                }
+                                first: 2
+                            ) {
+                                edges {
+                                    node {
+                                        Id
+                                        Subject {
+                                            value
+                                        }
+                                        AccountId {
+                                            value
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            `,
+            errors: [{ messageId: 'no-more-than-2-fields' }]
+        }
+    ]
+});